【作者】 朱林；

【导师】 梁宗锁；

【作者基本信息】 西北农林科技大学 ， 植物学， 2009， 博士

【摘要】 近年来,很多文献报道C3植物的碳同位分辨率(Δ¹³C)与蒸腾效率有很强的负相关关系而与产量正相关。因此,许多研究者建议把碳同位素分辨率(Δ¹³C)作为小麦蒸腾效率和产量的间接选择指标用于育种项目中。同时,由于Δ¹³C的测定分析成本较高,寻找与之密切相关的替代指标十分必要。为了研究宁夏不同生态条件下,碳同位素分辨率与产量以及与水分利用效率（WUE）相关的形态生理的关系,评价碳同位素分辨率在小麦高WUE品种筛选中的应用价值并筛选Δ¹³C的替代指标,在三种生态条件差异较大的小麦种植区,即银川（有限灌溉条件）、惠农（有限灌溉+盐碱条件）及固原（雨养条件）分别进行了多点试验,同时,又在一个试验点连续进行了三年田间试验,并做了三种土壤含水量处理的室外管栽试验,即45%±5%, 55%±5%和75%±5%田间持水量（FC）。在田间试验中采用20个、在管栽试验中采用10个春小麦基因型（地方品种、育成品种和高代材料）作为试验材料,测定了叶片及籽粒碳同位素分辨率、一些形态及生理指标,如灰分含量、比叶重、旗叶气体交换参数、相对含水量;研究了这些指标在不同试验点以及在同一试验点不同年份的遗传变异。在2008年小麦开花后,定期测定了主茎的比茎杆重和茎杆中碳水化合物的含量,计算了茎杆碳水化合物的积累效率和转运效率。分析了Δ¹³C与产量、所测定的形态生理指标、收获系数以及地上部生物量的关系。在2008年在银川和固原试验点分别种植了三个杂交类型的F6代,进行了田间小区试验,并测定了各株系的产量以及叶片、籽粒和基部茎杆的碳同位素分辨率。结果表明:1)在多点试验基础上,所测定的指标在不同试验点间有显著的差异,并且这种差异与水分条件密切相关。在银川试验点,籽粒Δ¹³C与产量呈显著正相关（r=0.737, P<0.001）。在银川和惠农试验点,籽粒Δ¹³C与收获系数呈正相关关系（r=0.637, P<0.01; r=0.472, P<0.05）;在惠农和固原试验点,旗叶Δ¹³C与收获系数显著正相关（r=0.605; P<0.01; r=0.509; P<0.05）。旗叶Δ¹³C在固原试验点与开花期旗叶相对含水量呈正相关（r=0.474, P<0.05）,在惠农试验点与灌浆期比叶重呈负相关（r=-0.528, P<0.05）。在惠农试验点,旗叶Δ¹³C与开花期单株干物重显著负相关（r=-0.475, P<0.05）;在固原试验点,旗叶及籽粒Δ¹³C均与开花期单株干物质重呈显著负相关（r=-0.626; P<0.01; r=-0.606; P<0.01）。在银川试验点,旗叶及籽粒Δ¹³C均与成熟期生物量显著负相关（r=-0.531; P<0.05; r=-0.539; P<0.05）;在惠农试验点,旗叶Δ¹³C与成熟期生物量间是显著负相关关系（r=-0.479, P<0.05）。在银川试验点,开花期旗叶温度与旗叶及籽粒Δ¹³C均呈显著负相关（r=-0.485; P<0.05; r=-0.521; P<0.05）;在惠农试验点,旗叶温度与旗叶Δ¹³C显著负相关（r=-0.475, P<0.05）;在固原试验点,旗叶温度与籽粒Δ¹³C显著负相关（r=-0.498, P<0.05）。在三个试验点,旗叶温度与气孔导度（gs）均呈显著的负相关（r=-0.856; P<0.01; r=-0.638; P<0.01; r=-0.517; P<0.05）。2)在三种土壤含水量处理的室外管栽中,测定的指标在不同的水分处理间有显著差异,不同来源的基因型间碳同位素分辨率有较大的差异,水地育成的品种或高代材料具有较高的Δ¹³C值,而旱地育成的品种或当地古老品种则表现出了较低的Δ¹³C值。在中度水分胁迫（T2）和正常灌水条件（T3）下,开花期旗叶Δ¹³C与开花期蒸腾效率显著负相关（r=-0.746, P<0.05; r=-0.696, P<0.05）,在重度水分胁迫（T1）和正常灌水条件（T3）下,籽粒Δ与蒸腾效率呈显著负相关（r=-0.852, P<0.001; r=-0.857, P<0.001）。在重度水分胁迫处理（T1）条件下,拔节期小麦地上整株、倒二叶以及扬花期旗叶中的灰分含量与旗叶Δ¹³C呈显著正相关（r=0.790, P<0.01; r=0.788, P<0.01; r=0.656, P<0.05）,成熟期籽粒Δ在中等水分胁迫（T2）和正常灌水处理（T3）下与籽粒灰分含量呈显著负相关（r=-0.695, P<0.05; r=0.721, P<0.05）。在中度水分胁迫处理（T2）下,扬花期旗叶中的钾（K）含量与旗叶Δ呈显著负相关（r=0.813, P<0.01）;在中度水分胁迫处理（T2）和正常灌水处理（T3）下,扬花期旗叶中镁（Mg）的含量与旗叶Δ¹³C呈显著正相关（r=0.725, P<0.05; r=0.826, P<0.01）;在正常灌水处理（T3）下,扬花期旗叶中钙（Ca）的含量与旗叶Δ¹³C呈显著正相关（r=0.708, P<0.05）,成熟期籽粒Ca含量与籽粒Δ呈显著负相关（r=-0.649, P<0.05）。在所有水分处理条件下籽粒Δ与成熟旗叶中Mg的含量都呈显著负相关（r=-0.753, P<0.01; r=-0.668, P<0.05; r=-0.695, P<0.05）。在严重水分胁迫条件下,收获系数与成熟旗叶灰分含量以Mg含量呈正相关;在中度水分胁迫条件下,收获系数与籽粒Ca含量呈显著正相关。3)在银川试验点多年试验中,由于2007年和2008年田间土壤含水量较低,小麦受到了花后水分胁迫,两年的产量与籽粒Δ¹³C（r=0.601, P<0.01; r=0.611, P<0.01）以及基部茎杆Δ¹³C（r=0.781, P<0.001; r=0.561, P<0.01）均呈显著正相关;2008年产量与旗叶Δ¹³C呈显著正相关（r=0.503, P<0.05）。2006年田间水分状况较好,产量与Δ¹³C不相关。成熟期基部茎杆Δ¹³C在2007年和2008年均与收获系数呈显著正相关（r=0.453, P<0.05; r=0.598, P<0.01）;在2006和2008年收获系数分别与旗叶Δ¹³C以及籽粒Δ¹³C显著正相关（r=0.536, P<0.05; r=0.663, P<0.01; r=0.563, P<0.01; r=0.467, P<0.05）。成熟期旗叶灰分含量在2006年和2007年都与籽粒Δ¹³C显著正相关（r=0.542, P<0.05; r=0.600, P<0.01）,在2007年与基部茎杆Δ¹³C显著正相关（r=0.540, P<0.05）。成熟期旗叶灰分含量在2006和2007两年间都与收获系数显著正相关（r=0.538, P<0.05; r=0.568, P<0.01）。灌浆期茎杆水溶性碳水化合物含量与籽粒Δ¹³C和基部茎杆Δ¹³C显著正相关（r=0.553, P<0.05; r=0.446, P<0.01）,开花后7天比茎杆重与旗叶Δ¹³C以及基部茎杆Δ¹³C呈显著正相关（r=0.567, P<0.01; r=0.453, P<0.05）。成熟期茎杆水溶性碳水化合物与产量呈显著负相关（r=-0.475, P<0.05）。茎杆水溶性碳水化合物（WSC）的转运效率分别与产量、旗叶Δ¹³C、籽粒Δ¹³C和基部茎杆Δ¹³C显著正相关（r=0.562, P<0.01; r=0.463, P<0.05; r=0.454, P<0.05; r=0.490, P<0.05）,总碳水化合物（淀粉含量与水溶性碳水化合物之和）的转运效率与籽粒Δ¹³C以及基部茎杆Δ¹³C显著正相关（r=0.531, P<0.05; r=0.444, P<0.05）。成熟期比茎杆重与籽粒Δ¹³C以及基部茎杆Δ¹³C都呈显著负相关（r=-0.473, P<0.05; r=-0.445, P<0.05）。4)在银川试验点,F6后代的Δ¹³C与产量显著正相关。而高Δ¹³C×高Δ¹³C组合F6代的叶片及籽粒Δ¹³C值都比高Δ¹³C×低Δ¹³C组合F6代的高,前者的产量也比后者高。同时,高Δ¹³C的后代也出现在高Δ¹³C×高Δ¹³C组合中。在固原试验点,在固原试验点,高Δ¹³C×低Δ¹³C组合F6代的Δ¹³C值介于高值亲本和低值亲本之间,而低Δ¹³C×低Δ¹³C组合的F6代籽粒及基部茎杆Δ¹³C值均比其亲本的高,并且前者的产量比后者的高。在低Δ¹³C×低Δ¹³C组合后代株系中,没有产量超过亲本的,而在高Δ¹³C×低Δ¹³C组合F6代中发现有许多优秀的株系产量超过高产亲本。同时,后者中各株系的产量差异较大,而前者中各株系产量差异较小。综上所述,1)在灌溉地区,高Δ¹³C是育种选择的目标。在雨养旱作区能否将碳同位素分辨率这一指标用于育种计划中要视播种时土壤含水量而定。在极干旱的年份不宜使用这一指标,而在土壤水分不是极其严酷,可以结合其他指标选择低Δ¹³C的基因型。2)三种器官中,基部茎杆Δ¹³C与花后茎杆碳水化合物向籽粒的转运效率、收获系数、物候期等的关系更强,似乎是产量最合适的间接选择指标。3)开花期旗叶中K、Mg含量、灌浆期比叶重、成熟期旗叶灰分含量、K、Mg含量以及籽粒Ca的含量可以作为Δ¹³C的替代指标有选择用于育种计划中。4)在银川灌溉条件下,高Δ¹³C×高Δ¹³C是比较好的杂交组合,高Δ¹³C是育种选择的目标。而在宁夏南部雨养旱作区,选择亲本时应选择Δ¹³C值差异较大的材料做亲本制杂交组合。更多还原

【Abstract】 Carbon isotope discrimination (Δ¹³C) has been reported to correlate negatively with transpiration efficiency （TE） and yield in C3 plants and been proposed as indirect selection criterion for transpiration efficiency and grain yield in wheat. Considering the high cost forΔ¹³C analysis, attempts have been made to identify alternative screening criteria. In order to study the relationships between carbon isotope discrimination （Δ）, yield and morphophysiological traits, to evaluate the value ofΔ¹³C in selecting high WUE （water use efficiency） wheat varieties and to screen the surrogates ofΔ¹³C, field experiments were conducted in three wheat growing regions with contrasting ecological conditions, i.e. Yinchuan （limited irrigation conditions）, Huinong （limited irrigation conditions + salinity） and Guyuan （rain-fed condition） of the Ningxia region （North-East of China） in years, and outdoor pot experiment, with three water treatments （45%±5% FC, 55%±5%FC and 75%±5%FC）, was carried out. 20 bread wheat cultivars, including landraces, released cultivars and advanced lines, were used in field experiments, while 10 wheat genotypes were used in pot experiment. Leaf, grain and basal stemΔ¹³C were analyzed, some morphophysiological traits such as, ash content （ma）, SLDW, gas exchange parameters, relative water content （RWC）, were measured. The genetic variation in these measured traits was studied among different experimental sites in one year and among different years in one experimental site. Relationships betweenΔ¹³C, grain yield （GY）, and the morphophysiological traits measured were analyzed. Correlations betweenΔ¹³C, harvest index （HI） and above-ground biomass （AGB） were also analyzed. In 2008, specific stem dry weight （SSDW） and carbohydrate in stem after anthesis were determined. The accumulation efficiency and remobilization efficiency of carbohydrate contents were also calculated. In 2008, F6 population derived from three crossing combinations were planted in Yinchuan and Guyuan. Randomized complete block experiment was carried out. The yield, carbon isotope discrimination in flag leaf and basal stem were measured, respectively.The results showed that: i) Differences for the measured traits between different locations were highly related to the variation in water availability. GrainΔ¹³C （ΔGm） was found to correlated positively to grain yield in Yinchuan （r=0.737, P<0.001）, and to HI in Yinchuan and Huinong（r=0.637, P<0.01; r=0.472, P<0.05）. Flag leafΔ¹³C （ΔLa） correlated positive with HI in Huinong and Guyuan （r=0.605; P<0.01; r=0.509; P<0.05）. Flag leafΔ¹³C positively correlated to RWC at anthesis in Guyuan（r=0.474, P<0.05）, and negatively to SLDW at grain-filling in Huinong（r=-0.528, P<0.05）. In Huinong, flag leafΔ¹³C was negatively related to dry matter weight per plant at anthesis（r=-0.475, P<0.05）which was found to associated negatively with flag leafΔ¹³C and grainΔ¹³C in Guyuan （r=-0.626; P<0.01; r=-0.606; P<0.01）. There were significant negative correlations between biomass at maturity, flag leafΔ¹³C and grainΔ¹³C in Yinchuan （r=-0.531; P<0.05; r=-0.539; P<0.05）. Flag leafΔ¹³C was also noted to biomass at maturity in Huinong r=-0.479, P<0.05). Flag leaf temperature （LT） at anthesis was found to be negatively correlated to flag leafΔ¹³C and grainΔ¹³C in Yinchuan （r=-0.485; P<0.05; r=-0.521; P<0.05）, to flag leafΔ¹³C in Huinong （r=-0.475, P<0.05）, and to grainΔ¹³C in Guyuan （r=-0.498, P<0.05）. Flag leaf temperature was also negatively correlated to stomata （gs） in all the three sites （r=-0.856; P<0.01; r=-0.638; P<0.01; r=-0.517; P<0.05）.ii) In the outdoor pot experiment carried out in Yinchuan, the traits measured showed significant differences among the three water treatments. There were variations inΔLa between the genotypes derived from contrasting environments. The improved varieties or advanced lines bred in irrigated areas displayed higherΔ¹³C values, while the improved and local varieties bred in rain-fed areas exhibited lowerΔ¹³C values. There were negative correlations between flag leafΔ¹³C and transpiration efficiency at anthesis（r=-0.746, P<0.05; r=-0.696, P<0.05）, while grain ? significantly and negatively correlated with transpiration efficiency under severe drought （T1） and well watered （T3） treatments（r=-0.852, P<0.001; r=-0.857, P<0.001）. Significant positive correlations were found betweenΔ¹³C and ma in seedlings and second fully developed leaves at elongation stage and in flag leaves at anthesis stage in severe drought treatment （T1） （r=0.790, P<0.01; r=0.788, P<0.01; r=0.656, P<0.05, respectively）. GrainΔ¹³C was correlated negatively with grain ash content under moderate drought （T2） and T3 treatments（r=-0.695, P<0.05; r=0.721, P<0.05）. Flag leafΔ¹³C was negatively associated with potassium （K） content in flag leaves in T2 （r=0.813, P<0.01） and positively with magnesium （Mg） content in flag leaves in T2 and T3 （r=0.725, P<0.05; r=0.826, P<0.01, respectively） at anthesis. Significant positive correlations betweenΔ¹³C and calcium （Ca） content in flag leaves at anthesis （r=0.708, P<0.05）, and betweenΔ¹³C and calcium （Ca） content in grain at maturity （r=-0.649, P<0.05） in T3 were also found in this study. GrainΔ¹³C was negatively associated with Mg content in flag leaf at maturity under all the three water treatments（r=-0.753, P<0.01; r=-0.668, P<0.05; r=-0.695, P<0.05）. Harvest index was associated with ma and Mg content in mature leaf under severe drought condition and Ca content in grain under moderate drought condition. Correlation was also found between K content in grain and GY.iii) In the multi-year experiments in Yinchuan, yield was positively correlated with grainΔ¹³C （r=0.601, P<0.01; r=0.611, P<0.01）, basal stemΔ¹³C （ΔSm） （r=0.781, P<0.001; r=0.561, P<0.01 ） were noted in 2007 and 2008, and with flag leafΔ¹³C in 2008 （r=0.503, P<0.05） when stress occurred after anthesis, but not in 2006 when soil water condition was nearly optimal. Ash content in mature flag leaf （maLm） correlated positively to grainΔ¹³C in 2006 and 2007（r=0.542, P<0.05; r=0.600, P<0.01）, to basal stemΔ¹³C in 2007 （r=0.540, P<0.05）, and to harvest index （r=0.538, P<0.05; r=0.568, P<0.01） in 2006 and 2007. In 2008, stem water-soluble carbohydrate content （WSC） at grain-filling was found to associated positively with grainΔ¹³C and basal stemΔ¹³C （r=0.553, P<0.05; r=0.446, P<0.01）. Specific stem dry weight 7 d after anthesis was positively associated with flag leafΔ¹³C and basal stemΔ¹³C （r=0.567, P<0.01; r=0.453, P<0.05）. Significant and negative correlation was recorded between stem WSC at maturity and yield （r=-0.475, P<0.05）. There were positive correlations between remobilization efficiency of stem water-soluble carbohydrate, yield, flag leafΔ¹³C, grainΔ¹³C, and basal stemΔ¹³C（r=0.562, P<0.01; r=0.463, P<0.05; r=0.454, P<0.05; r=0.490, P<0.05）. The remobilization efficiency of total carbohydrate （the sum of water-soluble carbohydrate and starch） was also found to be significantly and positively correlated to grainΔ¹³C and basal stemΔ¹³C （r=-0.473, P<0.05; r=-0.445, P<0.05）. There were negative relationships betweenΔGm,ΔSm, and SSDW at maturity （r=-0.473, P<0.05; r=-0.445, P<0.05）.iv) In Guyuan site, theΔ¹³C values of F6 population originated from highΔ¹³C×lowΔ¹³C crossing combination were between that of highΔ¹³C parent and lowΔ¹³C parent, theΔ¹³C values of F6 population originated from lowΔ¹³C×lowΔ¹³C were higher than their parents. The yield of F6 population originated from highΔ×lowΔcombination was higher than that from lowΔ×lowΔcombination. There was no F6 population derived from lowΔ¹³C×lowΔ¹³C, whose yield exceeded their parents, while a lot of elite lines were found in highΔ¹³C×lowΔ¹³C, with yield exceeding their high-yielding parent. The deviation of yield in the latter was larger than the former.To sum up, 1) HighΔ¹³C is the selection target in irrigated region, while the application ofΔ¹³C in breeding program depends the soil water content in rain-fed region. In extremely dry year, theΔ¹³C is not supposed to be used. Instead, in the year when the soil water stress is not very severe, theΔ¹³C, integrated with other traits, could be used. 2) Among theΔ¹³Cs in the three organs, basal stemΔ¹³C which showed strongest association with transportation of carobydrates to grain, harvest index and phenology, seems to be the best indirect indicator of yield. 3) The K, Mg contents in flag leaf at anthesis, specific leaf dry weight at grain-filling stage, ash content, K and Mg contents in flag leaf at maturity were found to have close association withΔ¹³C, and are suggested to be used in breeding program. 4) HighΔ¹³C×highΔ¹³C seems to be optimal crossing combination and the selection of progenies with highΔvalue would lead to yield gain in limited irrigation system （Yinchuan）, while the genotypes with contrastingΔ¹³C values should be adopted as parents in breeding program in rain-fed system （Guyuan）.更多还原